Slinky Toy Indoor Flag - By David Hamilton
After trying various types of loops ie multi turn loops,flags,pennants etc i have found the flag antenna best suited to my needs ie excellent back nulling and what "seems" good forward gain and with the space i have available ie 10 feet long and 7 feet high they do really work well for being indoors in my attic.
At my old qth i did have a 300 meter beverage for mw dx with two slinky toys inline to make it physically longer and it worked amazing and while trying to figure out how to make the loops better (its an ongoing job) i said to myself why not try the slinky toys in a loop as it would be the same size but physically longer ie each slinky (the usa ones) can be from 70 - 80 feet long.
You can get the slinky toys from any toy shop but i did try to find the original usa ones as i have found they are longer than the eu ones and the usa ones seem a better quality. In the loop i made i used two slinky's which would give me 130 - 140 feet of wire in my loop. I would recommend good quality electrical connector blocks for joining the slinky's or really heavy duty soldering.
I used one slinky for the top horizontal part and vertical drop and one slinky for the bottom horizontal and the other vertical side and i connected the balun on the side i wanted the maximum pick up and the variable resistor on the opposite corner that i wanted the null as i would do on my original flag antenna.
First test was with the resistor open and in theory it should give me a normal figure of 8 pattern and that should give me east west so i tuned around to see what i could hear. the normal ones were strong ie holland on 747 & 1008 khz and i did hear china on 1521 khz and also dutch pirates above 1600 khz and i did hear both irish stations on 846 and 981 khz so at least it "seemed" i was getting the figure of 8 pattern. The next test was to see if i could get a decent back null on it with a station to the east and this would "i hope" give me a good chance to get some clear signals to the west.
Holland on 1008 khz is a good test as its really strong here and if i could get any null on it i would be happy so i tuned the variable resistor and not only did i get a null i got rid of it altogether and in its place i got a spanish station. I also checked my local bbc scotland on 810 khz which is also to the back of the loop and was amazed to see it very weak and mixing with a spanish station so i had definately acheived a back null but would it give me a clear path to the west or is my lobe turning and going south ???.The next morning around 5 am i did check the conditions to the carribean etc and found rebelde cuba on 670 khz with a not too bad signal http://www.youtube.com/watch?v=1j9UyNJNfUc&feature=related so it "seemd" i was getting good direction to the west.
Not only that i was getting mexico on 1060 khz with the slinky loop but when i switched over to my north west flag i was getting a usa ans canadian mixing so it also "seemed" to have a tight lobe.If you are like me and cant get outdoor mw antennas or even short wave antennas dont be afriad to try the slinkys they do work but try and not place the coils to close and it will alow you to get alot of wire in a spce where you couldnt before.Testing the slinky flag is still ongoing and i will post results as i get them.
Have fun David H
